<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../react18/react.development.js"></script>
    <script src="../react18/react-dom.development.js"></script>
    <script src="../react18/babel.min.js"></script>
    <script src="../react18/prop-types.js"></script>
</head>
<body>
    <div id="app"></div>
    <script type="text/babel">
        /*
        字签串形式的Refs:
         -给被获取的元素添加一个ref属性，值是字符串（随意命名）
         -在组件实例上就会有一个ref对象，对象中有一个你设置的字符串属性，值是他代表的DOM
        */ 
   class Parent extends React.Component{
        render(){
            return(
                <div>
                    <input type="text" ref="oIpt"/>
                    <button onClick={this.handle}>点我弹出用户的输入内容</button>
                </div>
            )
        }
        
        handle =()=>{
            const{value}=this.refs.oIpt;
            alert(value)
        }
    
    
    }
    const root = ReactDOM.createRoot(document.getElementById('app'));
    root.render(<Parent/>)
    
    
    </script>
</body>
</html>